Objectives: Preventive workplace regulations are so far not based on an ubiquitously accepted threshold for airborne endotoxin in the bioaerosol.
Methods: In a cross-sectional study, 150 employees of a cotton spinning mill underwent lung function testing. Furthermore, in a random subset of 75 textile workers cross-shift lung function test and methacholine challenges were performed. Airborne current endotoxin exposure was classified as "low", "medium", and "high" (<or=100, >100-<or=450, and >450 Endotoxin Units (EU)/m(3), respectively) based on endotoxin activity.
Results: The exposure-response relationship between current endotoxin exposure and prevalence of an obstructive ventilation pattern was significant (test for linear trend: P = 0.019); the adjusted odds ratio for high endotoxin exposure was 11.22 (95% confidence interval 1.03-121.17). Within individuals, FEV(1)/FVC% was significantly reduced after the shift (paired t test: P = 0.009) but not related to current endotoxin exposure. Twelve workers showed bronchial hyperresponsiveness (8.1% before and 12.2% after the work shift; Fisher's exact test: P = 0.021).
Conclusion: The study among German cotton textile workers suggests an exposure-dependent effect of current endotoxin exposure on lung function impairment with significant effects above 450 EU/m(3).